Serpentine belts are present on most U.S. and import vehicles in the United States. The serpentine belt is the one found in the engine area that connects major vehicle functions, such as water pumps, alternators, air conditioning etc. The belt is spring-loaded and requires a special tool to release the spring tension to remove and replace the belt. Depending on the vehicle, the tension device is moved by placing the tool on either a bolt in the tension arm or a female square drive that is molded into the tension arm. Access to the bolt is limited, and therefore a specialty tool is required.
Approaches to releasing the tension vary, but in all cases there are members that attach to the tool, and the tool is used to fit onto a serpentine belt idler pulley work piece.